Electronic appliances are available such as, for example, television receivers equipped with an organic electro-luminescent (hereinafter, referred to as “organic EL”) display apparatus or a liquid crystal display apparatus. In such electronic appliances, light-emitting elements arranged in a matrix to constitute an organic display apparatus or a liquid crystal display apparatus are driven by a plurality of thin-film transistor (TFT) devices.
A TFT is formed by, for example, forming a source electrode and a drain electrode, a semiconductor layer (channel layer), a gate insulating film, and a gate electrode in sequence on a substrate, and a thin film made of silicon semiconductor is commonly used as a channel layer of the TFT (see, for example, Patent Literature (PTL) 1).
Silicon semiconductor thin films are roughly classified into non-crystalline silicon (amorphous silicon, a-Si) thin films; and silicon thin films (crystalline silicon thin films) having crystallinity. The crystalline silicon thin films can be further classified into polycrystalline silicon thin films, microcrystalline silicon thin films, monocrystalline silicon thin films, and the like.
Among them, currently, the non-crystalline silicon thin films are most commonly used as channel layers for use in elements for large-screen liquid crystal displays because they can be formed uniformly on large-area substrates at a relatively low temperature by chemical vapor deposition method (CVD method) or the like. The non-crystalline silicon thin films, however, are inferior to the crystalline silicon thin films in terms of characteristics such as carrier mobility. For this reason, it is eagerly desired to achieve a TFT that includes a crystalline silicon thin film as a channel layer, so as to achieve a display that quickly starts working and has a high definition.
Under the circumstances, techniques for forming a crystalline silicon thin film have been proposed (for example, PTLs 2 to 4).